Micellization of sodium bis(2-ethylhexyl)sulfosuccinate in supercritical CO2 with fluorinated co-surfactant and its solubilization of hydrophilic species
- 作者：Liu ; Juncheng ; Shervani ; Zameer ; Raveendran ; Poovathinthodiyil ; Ikushima ; Yutaka
- 关键词：Supercritical CO2 ; AOT ; Fluorinated co-surfactant ; Microemulsions ; Hydrophilic species
- 刊名：The Journal of Supercritical Fluids
- 出版年：2005
- 期刊代码：60_08968446
- 类别：ce
- 出版时间：February, 2005
- 卷：33
- 期：2
- 页码：121-130
- 文件大小：316 K
摘要
The solubilities of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in supercritical CO2 (scCO2) in the presence of ethanol, 1-pentanol and 2,2,3,3,4,4,5,5-octafluoro-1-pentanol (F-pentanol) at 38.0°C and different pressures were determined. It was found that AOT (0.01–0.07M) could be solubilized in scCO2 with smaller amount of F-pentanol (0.20–0.30M) compared with ethanol (1.00–1.40M) and 1-pentanol (0.60–1.00M), because F-pentanol has ‘CO2-philic’ fluorinated alkane chain. The phase behavior studies for AOT (0.03M)/F-pentanol (0.18–0.35M)/scCO2 system ranging in temperature from 38.0 to 52.2°C and pressures up to 35.00MPa indicated that the cloud point pressure of AOT decreased significantly with the addition of F-pentanol, and the lower temperature, the lower cloud point pressure of AOT especially at higher concentrations of F-pentanol. In addition, 0.016M AOT/0.24M F-pentanol/scCO2 system could solubilize a significant amount of water ( Formula Not Shown, and Formula Not Shown ) at moderate conditions, which implied the formation of water-in-CO2 reverse microemulsions. Visual observation using a video camera on the solubilization of methyl orange (MO) further proved the existence of polar micro-water domains within the AOT W/C reverse microemulsions. Besides that, bio-macromolecules such as cytochrome c and lysozyme and 8-hydroxy-1,3,6-pyrenetrisulphonic acid trisodium salt (HPTS) characteristic of highly ionic property could be solubilized in the microemulsions, which was obviously reflected by the UV–vis spectra.